Engine pressure regulator



Nov. 11, 1941.

w. G. LuNDQulsT Erm.

ENGINE PRESSURE REGULATOR 2 Sheets-Sheet 1 2 max mxon'm lNvEm-ons Mmylmwawsrm BY* Rum yzLToN ATronNEY '5 Nov. 11, 1941.

w. G. LuNDQuls'r |:rAL 2,262,022

ENGINE PRESSURE REGULATOR I Filed Maron 4, 1939 2 Sheets-Sheet 2 torque and henceinpractical power control techincludes a bell gear I on the crankshaft I4 nique, it is necessary for the operator to use which engages planet pinions I6 journalled on correction factors to cover these variations. a spider I 6 which is rigid with the propeller shaft The prime object of the present invention is to I3. An oscillating but non rotating sun or reprovide automatic manifold pressure control re- :action gear Il' is carried by a hub Il on an ansponsive to the actual torque output of the ennular bracket I1" ysecured to the engine nose.

Patented Nov. 1.1, 1941 i I UNITED STATES PATENT OFFICE ENGINE PRESSURE REGULATOR Wilton G. Lundqnist, Glen Rock, and Roland Chilton, Ridgewood, N. J., assgnors to Wright Aercllxnantical Corporation, a corporation of New Yor Application March 4, 1939, Serial No. 259,786 4 Claims. (Cl. 12S-103) This invention relates to means for controlling Fig. 6 is an enlarged section through an enthe torque and po'wer outputs of internal comgine reduction gear showing same in a more debustion engines. The primary factor determintailed manner than is indicated in Fig. 1; and ing the torque (and therefore the power output Fig. 'I is an enlarged detailed section of a porat constant speed) is the manifold pressure, 5 tion of Fig. 2. which is controlled by the throttle and auto- Referring rst to Fig. 1, we show an engine matic devices for maintaining constant manifold I0 indicated as a radial air-cooled engine. The pressure, such devices being old in the art. rear end of the main housing carries a carbu- Except when conditions as to manifold temretor II provided with a throttle lever I2. From peratures, mixture strength and cylinder teml0 the front end of the engine a propeller shaft I3 peratures are held constant, manifold pressure is projects which is driven from a crankshaft I4 only an approximate index of the actual output through a reduction gear. This reduction gear gine regardless of the instant temperature and The reaction gear hub I1 is associated with a mixture strength conditions. The control for torque meter I8 in a manner which should be the manifold pressure regulating device is, acapparent from Fig. 2. The specific details of cording to the teachings of this invention, dethe reduction gear and of the torque meter form rived from uid pressure governed to be directly no specic part of the present invention and some proportional to the true engine torque. of the specific details of such a torque meter are It is a further object of this invention to proshown in the co-pending application of Roland vide a throttle adjusting system' which'is re- Chilton, Serial No. 248,052, filed December 28, sponsive directly to the actual output torque of 1938: the engine or to the mean pressure in the engine Figs. 2, 4 and' 5 show embodiments utilizing Cylinders Which is truly PrOpOriiDnal i'fO torquesuch atorque meter and Figs. 2 and 7 show the It is a further object of the invention to devise torque meter construction. Referring again to an automatic thrtile adjusting means which Fig. 1, the torque meter I8 produces hydraulic may at any time be overcontrolled by an operpressure in a pipe I9 whichis proportional to ator.v Objects of the invention further comprise engine torque, the pipe I9 communicating with the prOVisOn Of a torque adjusting device actuan automatic throttle control mechanism 20, this ated by engine oil pressure and sensitive to mechanism carrying a slidable rod 2| to which changes in torque as measured by torque mea bell crank 22 is pivoted at its center. The ters wllich have been developed for particular ends of the bell crank 22 are respectively conapplication to aircraft engines. Still another obnected to the throttle lever I2 and to a manual ject is to provide an automatic throttle adjustl throttle control through a rod 23. The rod 2| ing device which may be directly actuated by 4o is automatically controlled axially, in a manner fluid pressures resulting from ilOrque either With shortly to be described, and it will be seen that or Without the interposition of a servo mechaif the rod 23 is xed, sliding of the rod 2I lto nism. the left will increase throttle opening. If the Further objects will become apparent in readrod 2I be relatively fixed, movement-of the rod ing vthe annexed description in connection wit-h '23 to the right will serve to increase throttle the drawings, in which opening. Assuming a fixed hand throttle, the Fig. 1 is a side elevation of an aircraft engine rod 2| will be moved to the left should torque incorporating the mechanism of the invention; developed by the engine decrease, thus causing,

Fig. 2 is a composite section of devices which an increase in throttle opening and an increase comprise the control system; 50 in torque until a balanced condition is reached. a Fig. 3 is a diagrammatic elevation, partly in .Now referring to Figs. 2 and '7 it will be seen section showing an alternate control arrangethat the torque meter I8 comprises a piston 26 ment; the head of which is slidable in a cylinder 21, the

Figs. 4 and 5 are vrespectively sections through opposite end of the piston 26 abutting against the alternate embodiments of'the. invention; l 55 reaction gear hub I1. A hydraulic pump 28 conscribed is as follows:

"the gear hub l1. This pressure will be of the order of several hundred pounds per square inch and the fluid is led through a damping valve 30 toy a small cylinder 3| tted with a piston 32 integral with a large piston 33 slidable in a cylinder 34. In the housing of the cylinder 3|, a port 35 is provided whch communicates through a suitable drilling to a valve groove 36 in the cylinder 32, the groove communicating through a central drilling 31 in the piston, with the cylinder 34. This last described mechanism comprises a pressure reducing valve so that the pressure in the cylinder 34 is continually proportional to that in the cylinder 21 in a ratio determined by the relative areas of the-piston 32 and the piston 33. The low pressure existing in the cylinder 34 is communicated through a conduit 40 to the control device 28 which in eect'is a servo control to adjust the position of the rod 2| in accordance with the torque-proportional pressure. The unit 20 comprises a bellows 42 subject to fluid pressure fromv the conduit 48, the bellows carrying a valve arm 43 and a valve 44, the bellows being balanced by a spring adjustable as to force imposed by a screw control 46. The valve 44 is seated in a chamber 41 supplied with engine presure oil in its mid-portion through a passage 48, spaced portions of the chamber 41 communicating through ports 49 and 50 with a cylinder 5l in which is a piston 52 which controls the rod 2|. The valve 44 serves to place one or the other end of the cylinder 5| in communication with engine oil pressure source to eifect movement of the piston 52, the opposite opening in the cylinder being coincidentally connected with the interior of the unit 28 which is drained through an opening 53, the ends of the chamber 41 freely communicating with the interior of the device 28.

The operation of the mechanism above de- The adjusting screw 48 may be preset for any desired engine torque and with the engine idle, the spring 45 will hold the valve 44 in such a position that engine oil flows into the right hand end of the cylinder 5| to effect an increase in throttle opening. As the torque of the engine increases to the: desired value, pressure fluid will enter the bellows 42, deflecting the spring 45 to close the valve 44, holding the throttle in that position which maintains the desired -torque preset by the control 46. Any variations in torque thereafter will be compensated by increasing or decreasing the throttle opening so that the preset torque is maintained within reasonable operating limits.

Fig. 4 shows an alternative arrangement similar in principal to that of Fig. 2, wherein fluid pressure from the torque meter i8 is imposed through a piston 59 against the adjustable balancing spring 58, a valve arm 43 and valve 44 functioning in response to torsional variations in the previously described manner. A drain passage 52 provides for exit oil ow from the left hand end of the cylinder 5| to the drain opening.

53 when the valve 4 4 is moved toward the right. The unit in Fig. 4 is designated as 20 and elements therein having similar functions to the y device 20 are indicated by the same reference characters.

In Fig. 5 pressure iluid from the torque meter |8 is carried through the conduit 48 to an adjusting device 65 which comprises at its left hand end a cylinder 66 within which a plunger 81 is slidable, the plunger being sealed with respect to the cylinder by a exible sleeve 68. The plunger 81 extends to the right into a cavity in the device which contains a plurality of stout springs 89, adjustable as to their compression by a screw device 10, these springs bearing upon a flange 1| on the plunger. Thus, the springs 59 serve to balance directly the pressure from the torque meter. The plunger is provided with ilanges 12 on opposite sides of a yoke 13 which is the inner terminal for a lever 14 pivoted at 15 to the device and extending therebeyond to carry the bell crank 22 to which throttle connections are made as previously described. In this embodiment'the bell crank 22 is operated directly, without the interposition of a servo mechanism, by the torque meter pressure. Since the torque meter pressure available is high, the diameter of the plunger 61 may be made moderately small and the spring 69 may be sufficiently stii so that considerable force may be imposed upon the bell crank 22 without appreciably altering the position of the lever 14. Since the throttle control rod, such as 23 in Fig. 1 is subjected to a friction drag of about 40 lbs., it will `be appreciated that the stability of the lever 14 must be quite great in order not to deflect unduly when throttle moving forces are imposed manually by the operator.

The servo arrangement shown in Figs. y2 and 4 provide an irreversible hydraulic positioning de- 'vic'e for the bell crank 22 which is not alterable due to manually imposed throttle changing forces. The particular arrangement of Fig. 2 is convenient in that the device 20 shown therein is substantially identical structurally with an existing manifold pressure responsive throttle control device. The three arrangements of Figs. 2, 4 and 5 respectively are virtually identical in principal but differ in the order of torque proportional pressures by Whlchthey are operated.

The arrangement of Fig. 3 shows an apparatus which is operated directly by the mean pressure existing within the engine cylinder which, of course, is proportional to torque. In this arrangement, an engine cylinder communicates with an anti-fluctuation chamber through a pipe 82 and an orifice 83, the chamber 8| in turn communicating with a second chamber 84 through a pipe 85 and an orifice 86. Additional chambers may be provided if desirable, and these serve the function of successively damping the violent pressure changes in the cylinder to the average pressure existing therein. In other terms, then,

the substantially constant pressure in the last' chamber 84 is the M. E. P. of the engine. This pressure is communicated through a pipe 81 to a' throttle changes are efIected in response to a pressure proportional to torque.

By utilizing the teachings of this invention constant torque operation of an engine is aiorded, and when this is used in connection with a constant speed propeller in an aircraft engine, constant power operation is afforded.

: .-.While we have described our invention in detail in its present preferred embodiment, it will be obvious to those skilled in the art, after understanding our invention, that various changes and modifications maybe made therein without departing from the spirit or scope thereof. We aim in the appended claims to cover all such modications and changes.

What we claim is:

1. In an internal combustion engine including a throttle in combination, a, plurality of serially connected pressure balancing chambers, a piston chamber open to the rst chambers to receive a pressure therein proportional t0 the M. E. P. of the engine, a piston in said piston chamber, resilient means to. urge said piston into said chamber against said pressure,v wherefore pressure variations may move the piston against said resilient means, and means actuated by piston movement for opening and closing said throttle.

2. In an internal combustion engine including a throttle in combination, a balancing chamber connected to an engine cylinder, a pressure chamber connected to the balancing chamber to receive a pressure therein proportional to the M. E. P. of the engine, a piston in said pressure chamber, resilient means to urge said piston into said chamber against said pressure, wherefore v pressure variations may move the piston against ance the motor'at a certain position, and means l said resilient means, and means for adjusting said resilient means to establish a datum position chamber against said pressure, wherefore pressure variations may move the piston against said spring, and a servo valve actuated by piston movement for opening and closing said throttle. 4. In an internal combustion engine including a throttle in combination, a uid pressure device responsive to the pressure exerted thereby to the M. E. P. under which the engine' is operating,

a motor connected to said device, resilient means in the motor opposing the uid pressure to balresponsive to excursions of said motor from its certain position to actuate the engine throttle. VWILTON G. LUNDQUIST.

ROLAND CHILTON. 

